This has been raised as an incident and is actively being work on for a solution.
It's on the incident dashboard which you can find here
https://community.talktalk.co.uk/t5/Service-Status-Dashboard/bd-p/service
Updates will be posted there.
Please remember to mark Solved Posts with Best Answer. Doing so helps other customers and saves TalkTalk's Support Team time by only looking at unsolved topics. Thanks, Steve (a fellow customer).
